When my guy's eyes clear up I've been throwing in a warm moist washcloth. I tried moss but he just pushes it out of the hid anymore, I don't think he likes the smell. I'll leave the washcloth between his 2 hides. Works great if you can get him to figure it out, he should be rubbing his nose on it when he's ready. Definitely wait for the eyes to clear.. he will be much less stressed when you add stuff to his home.
I have echoearth cocohust as my substrate. I boil it every 2 or 3 weeks, depending on when he drops a load. Let it evaporate some and squeeze the excess water out. You will never have to worry about humidity gain, so long as you can control the airflow out of the top of the cage. And you probably wont need to replace it for years.
Here's what I use for bulbs.
Here's what my tank looks like.
Bear in mind, compared to many happy, thriving snakes, my setup is overkill.
You are only as good as your tools.. Laser-thermo and a hygrometer are a must, you can get away with no UTH (Though he will probably appreciate having one) but bare minimum I would get atleast one thermostat.